Antenna windshield

Abstract

An improved and laminated antenna window for vehicles and the like in which antenna wire is embedded in interlayer material and extends out of a surface of the interlayer material into a notched area for attachment to an electroconductive element adapted to be coupled to a radio receiver. A thin layer of a plastic material having a lower deformation temperature than the interlayer material is used in the vicinity of the notched portion to provide a barrier against fluid penetration between the layers of the assembly to be laminated, thereby insuring a product that is acceptable to the customer.

We claim: 
     
       1. A laminated antenna window comprising a pair of relatively rigid sheets of transparent material, a notched portion along the marginal portion of one of said sheets, a thermoplastic organic interlayer bonding said rigid sheets together throughout substantially their entire extent, antenna wire embedded in said interlayer and having a portion extending outward from a major surface of said interlayer in the vicinity of said notched portion, and a film of organic plastic having a lower heat-softening temperature than that of said interlayer and adherent to said antenna wire, said rigid transparent material and said interlayer disposed between said notched rigid sheet and said interlayer in the vicinity of said notched portion, said plastic film being sufficiently thick to prevent fluid penetration along said wire laterally interiorly of said notched portion during the lamination of said laminated antenna window in an oil autoclave. 
     
     
       2. A laminated antenna window as in claim 1, wherein said transparent material is glass. 
     
     
       3. A laminated antenna window as in claim 2, wherein said interlayer is plasticized polyvinyl butyral. 
     
     
       4. A laminated antenna window as in claim 3, wherein said plastic film consists essentially of a polyurethane having a heat-softening temperature below that of said plasticized polyvinyl butyral. 
     
     
       5. A laminated antenna window as in claim 4, wherein said plastic film consists essentially of a polyurethane composition consisting essentially of the reaction product of a cycloaliphatic diisocyanate and a hydroxy-terminated aliphatic glycol having a number average molecular weight between about 500 and 800, containing no more than about 7 percent by weight of residual unreacted glycol, the mole ratio of diisocyanate to polyester being such that the polyurethane is essentially free of unreacted isocyanate groups. 
     
     
       6. A laminated antenna window as in claim 5, wherein said polyurethane composition includes less than 0.05 percent by weight of gamma-glycidoxy-propyltrimethoxysilane based on said polyurethane. 
     
     
       7. In the method of fabricating a laminated antenna window comprising a pair of sheets of rigid transparent material, a notched portion in a marginal portion of one of said sheets, an organic interlayer sheet, antenna wire embedded in said interlayer sheet and having a portion thereof extending from said interlayer sheet into said notched portion wherein said pair of sheets and said interlayer sheet are assembled to form a sandwich and prepressed to remove fluid from the interfacial surfaces of said sandwich and then subjected to heat and pressure in an oil autoclave to complete the lamination of said window, the improvement comprising applying a film of an organic plastic material having a lower heat-softening temperature than said organic interlayer sheet and adherent to said antenna wire, said rigid transparent material and said interlayer sheet to a surface of said notched sheet in the vicinity of said notched portion, assembling said two sheets of rigid transparent material and said interlayer sheet to form a sandwich of aligned sheets in such a manner that said film of plastic material is on a surface of said notched sheet facing said interlayer sheet and said extending portion of said antenna wire, and applying sufficient heat to said sandwich during the prepressing thereof to flow said plastic material around sufficient of said extending portion of said antenna wire to form a dam sufficient to inhibit the inward flow of oil along the length of said antenna wire during the heat and pressure exposure in said oil autoclave. 
     
     
       8. The method as in claim 7, wherein said sheets of rigid transparent material used to assemble said sandwich are glass sheets, said interlayer sheet used to assemble said sandwich is plasticized polyvinyl butyral, and said film of plastic material applied to said notched glass sheet is a polyurethane composition. 
     
     
       9. The method as in claim 8, wherein said polyurethane composition applied to said notched glass sheet consists essentially of the reaction product of a cycloaliphatic diisocyanate and a hydroxy-terminated aliphatic glycol having a number average molecular weight between about 500 and 800, containing no more than 7 percent by weight of unreacted glycol, the mole ratio of diisocyanate and polyester being such that the polyurethane is essentially free of unreacted isocyanate groups. 
     
     
       10. The method as in claim 9, wherein said polyurethane composition applied to said notched glass sheet further includes less than 0.05 percent by weight of gamma-glycidoxy-propyltrimethoxysilane based on said polyurethane.